/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.testing;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.Beta;
import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Lists;
import com.google.errorprone.annotations.concurrent.GuardedBy;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * A {@code TearDownStack} contains a stack of {@link TearDown} instances.
 *
 * <p>This class is thread-safe.
 *
 * @author Kevin Bourrillion
 * @since 10.0
 */
@Beta
@GwtCompatible
public class TearDownStack implements TearDownAccepter
{
    private static final Logger logger = Logger.getLogger(TearDownStack.class.getName());

    @GuardedBy("stack")
    final LinkedList<TearDown> stack = new LinkedList<>();

    private final boolean suppressThrows;

    public TearDownStack()
    {
        this.suppressThrows = false;
    }

    public TearDownStack(boolean suppressThrows)
    {
        this.suppressThrows = suppressThrows;
    }

    @Override
    public final void addTearDown(TearDown tearDown)
    {
        synchronized (stack)
        {
            stack.addFirst(checkNotNull(tearDown));
        }
    }

    /**
     * Causes teardown to execute.
     */
    public final void runTearDown()
    {
        List<Throwable> exceptions = new ArrayList<>();
        List<TearDown> stackCopy;
        synchronized (stack)
        {
            stackCopy = Lists.newArrayList(stack);
            stack.clear();
        }
        for (TearDown tearDown : stackCopy)
        {
            try
            {
                tearDown.tearDown();
            }
            catch (Throwable t)
            {
                if (suppressThrows)
                {
                    logger.log(Level.INFO, "exception thrown during tearDown", t);
                }
                else
                {
                    exceptions.add(t);
                }
            }
        }
        if (!suppressThrows && (exceptions.size() > 0))
        {
            throw ClusterException.create(exceptions);
        }
    }
}
